It is a skin disorder where the skin abnormally responds to the sunlight, especially the Ultra-violate (UV) rays, which lead to rash on skin. The skin rash could lead to itching, burning and swelling. This can lead to darkening of the skin subsequently.As they one can have allergy or sensitivity to anything under the sun, including the sun. Yes, there is a disease in which one tends to be allergic or sensitive to sunlight. That is called Photodermatitis or photosensitivity.   

CAUSES OF PHOTODERMATITIS

•  body's inherent tendency to react to sunlight.
• There are some chemicals and medicines which may make one prone to have such hyper-sensitive, which include certain antibiotics, anti-diabetic drugs, psoralens, coal tars (used for psoriasis), salicylanilide (industrial chemical). Vitamin B3 (niacin) deficiency can also trigger photosensitivity.

SYMPTOMS OF PHOTODERMATITIS

•  rash on the sun-exposed areas such as face, arms, hands, back or all over the body (in case of sub-bathing).
• Reddening of skin with itching, mild scaling, burring and pain.
•  there could be mild, thin, watery discharge.
• The skin tends to turn dark or black subsequently in many patients, especially on face.
• Darkening of the skin may not disappear on stopping of exposure to sun, unfortunately.

HOMOEOPATHIC MEDICINES FOR PHOTODERMATITIS

Natrum Mur

Natrum Mur is an effective homeopathic medicine for treating itchy skin in cases of photodermatitis. Skin worsened by exposure to the sun respond well to Natrum Mur. It is indicated in cases where there is itching, prickling, and stinging sensation, or crawling sensation. Rash or vesicles may also be present on the skin. These blisters tend to burst and discharge watery fluid. 

Cadmium Sulph 

atural cure for photodermatitis where there is skin pigmentation that arises from sun exposure. The pigmentation is most marked on the face; sometimes the skin is itchy too. Itching worsens mostly during the night, and scratching tends to relieve the itching.

Sulphur 

Homeopathic medicine Sulphur is an effective remedy to treat a burning sensation on the skin in cases of photodermatitis. The burning may be localized or spread on the skin throughout the body. The burning sensation is worse at night time in a majority of the cases. Sleep is often disturbed due to this burning sensation. The skin may be dry and rough, and swelling may be present. 

Glonoine 

headache following sun exposure in cases of photodermatitis.  the headache is most prominently congestive with intense throbbing pains in the head. In some cases, the eyeballs may protrude out. Headache may be attended with nausea and is mostly felt in the temporal (sides) region and vertex (top) of the head. Sleep tends to relieve the headache. A marked heated sensation in the head is also present along with the headache.